KR20090037689A - Scalable video encoding method and apparatus and scalable video decoding method and apparatus - Google Patents

Abstract

A scalable image encoding method and apparatus and a scalable image decoding method and apparatus are provided to apply features that each codec has to prediction between layers, thereby providing an image of better quality. A down scaling unit(110) controls picture quality about an inputted original image. A basic layer encoding unit(120) produces a basic layer restoration image by decoding a basic layer bit stream. An up scaling unit increases resolution of the restoration image by using interpolation with regard to the restoration image. The up scaling unit produces new frames by using the frames of the restoration image. The up scaling unit inserts generated frames into a frame of the restoration image.

Description

Scalable video encoding method and apparatus and apparatus and method for decoding the same {Scalable video encoding method and apparatus and scalable video decoding method and apparatus}

The present invention relates to a scalable video encoding method and apparatus, and a video decoding method and apparatus.

Scalable video coding (SVC) refers to encoding an image into a bitstream having multiple layers. The scalable video encoding bitstream enables the decoder to decode using several layers selectively among the bitstreams. This bitstream is composed of a base layer and one or more enhancement layers. The base layer bitstream is the most basic bitstream, which can be used to reconstruct the image with minimal image quality. If the enhancement layer bitstream is used in addition to the base layer bitstream, the image can be reconstructed with better image quality. At this time, only the base layer bitstream is decoded according to the available transmission bandwidth or the user terminal, or both the base layer bitstream and the enhancement layer bitstream are decoded.

Such scalable video encoding technology is used in various video compression standards such as MPEG-2, MPEG-4, H.263 and H.264, and is expected to be applied to more various video codecs in the future.

An object of the present invention is to provide a scalable image encoding method and apparatus for encoding by applying one of a plurality of codecs as a base layer and applying characteristics common to each codec to inter-layer prediction. Another technical problem to be solved by the present invention is to provide a scalable video decoding method and apparatus for decoding by applying an arbitrary codec as a base layer and applying characteristics common to each codec to inter-layer prediction. Further, the present invention provides a computer-readable recording medium having recorded thereon a program for executing the above-described methods on a computer.

According to an aspect of the present invention, there is provided a scalable video encoding method comprising: generating a base layer bit stream for an image using any one of a plurality of codecs; Determining whether a codec used for generating the base layer bit stream is a codec for which enhancement layer encoding is supported; Extracting encoding information used to generate the base layer bitstream by decoding the base layer bitstream according to the determination result; And generating an enhancement layer bitstream for the original image by using the extracted encoding information.

According to another aspect of the present invention, there is provided a scalable video encoding apparatus comprising: a base layer encoder for generating a base layer bit stream for an image using any one of a plurality of codecs; A codec determination unit that determines whether a codec used for generating the base layer bit stream is a codec for which enhancement layer encoding is supported; A symbol extraction unit configured to extract encoding information used to generate the base layer bitstream by decoding the base layer bitstream according to the determination result; And an enhancement layer encoder for generating an enhancement layer bitstream of the original image by using the extracted encoding information.

According to another aspect of the present invention, there is provided a scalable video decoding method comprising: separating an input bitstream into a base layer bitstream and an enhancement layer bitstream; Determining whether the codec used for encoding the separated base layer bitstream is a codec for which enhancement layer decoding is supported; Extracting predetermined information by decoding the separated base layer bitstream according to the determination result; And performing decoding on the separated enhancement layer bitstream using the extracted predetermined information.

In order to solve the above further technical problem, the present invention provides a computer-readable recording medium that records a program for executing the scalable image decoding method on a computer.

According to an aspect of the present invention, there is provided a scalable video decoding apparatus comprising: a bitstream separator configured to separate an input bitstream from a base layer bitstream and an enhancement layer bitstream; A codec determination unit that determines whether a codec used for the separated base layer bitstream is a codec for which enhancement layer decoding is supported; An information extracting unit which extracts predetermined information by decoding the separated base layer bitstream according to the determination result; And an enhancement layer decoder configured to perform decoding on the separated enhancement layer bitstream using the extracted predetermined information.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a configuration of a scalable video encoding apparatus according to an embodiment of the present invention.

As illustrated in FIG. 1, the scalable video encoding apparatus 10 according to the present exemplary embodiment may include a downscaling unit 110, a base layer encoder 120, an upscaling unit 130, a subtracting unit 140, A codec discrimination unit 150, a symbol extractor 160, an enhancement layer encoder 170, and a bitstream integrator 180 are included.

The down scaling unit 110 performs down scaling for adjusting the image quality of the input original image. In particular, the downscaling unit 110 may use various downscaling depending on the scalability of the scalable video encoding apparatus 10 to use the scalability.

As an example, the downscaling unit 110 may lower the screen resolution by subsampling a frame of an original image in a horizontal direction and a vertical direction. As another example, the downscaling unit 110 lowers the frame rate of the original image by removing some of the frames constituting the original image. As another example, the downscaling unit 110 may convert an image format. When the original image is a 4: 4: 4 image format, the downscaling unit 110 performs down sampling on the chrominance block to perform an original image. You can convert to 4: 2: 2 or 4: 2: 0 video format. In this case, the 4: 4: 4 image format means that three components, luminance component Y, chrominance component Cb, and Cr, respectively exist at positions of all pixels, and the 4: 2: 2 image format is a chrominance component. Cb and Cr have the same resolution as the luminance component Y in the horizontal direction, but have a half resolution of the luminance component Y in the vertical direction, and the 4: 2: 0 image format is Cb and Cr as the chrominance component. Means that the resolution is 1/2 in the horizontal and vertical directions compared to the luminance component Y. As another example, the down scaling unit 110 may reduce the bit depth such as changing the bit depth of the pixels constituting the original image from 8 bits to 6 bits. The downscaling by the downscaling unit 110 may perform various other functions according to the scalable video encoding technique, and the downscaling unit 110 according to the present embodiment is not limited to the above-listed methods. The downscaling unit 110 may be omitted in some cases.

The base layer encoder 120 generates a base layer bitstream by encoding the down-scaled image by the down scaler 110 through predictive encoding, motion compensation, orthogonal transformation, quantization, and entropy encoding. A base layer reconstruction image is generated by decoding the base layer bitstream. In particular, in order to perform encoding for generation of a base layer bitstream, the base layer encoder 120 may include an H.264 baseline profile, an H.264 main profile, a VC-1 simple profile, a VC-1 advanced profile, and an MPEG- You can use any one of the following tokcode compatible with existing video compression standards: 4 part2 simple profile, MPEG-4 part2 advanced simple profile, MPEG-4 part2 main profile, and H.263 baseline profile.

The upscaling unit 130 performs the upscaling on the base layer reconstructed image generated by the base layer encoder 120, which is the opposite process of downscaling of the downscaling unit 110. Create That is, if the resolution of the image is lowered by the down scaling unit 110, the upscaling unit 130 increases the resolution of the reconstructed image by using interpolation for the reconstructed image. If the frame rate is lowered by the downscaling unit 110, the upscaling unit 130 generates new frames using the frames of the reconstructed image, and then inserts the generated frames into the frames of the reconstructed image. To increase the frame rate. In addition, if the image format of the original image is converted by the downscaling unit 110, the image format of the reconstructed image is converted to match the image format of the original image. If the bit depth is reduced by the down scaling unit 110, the up scaling unit 130 restores the bit depth again. The upscaling by the upscaling unit 130 may perform various other functions according to the scalable video encoding technique, and the upscaling unit 130 according to the present embodiment is not limited to the above-listed methods. The upscaling unit 130 is a component that may be omitted in some cases, like the downscaling unit 110.

The subtractor 140 obtains a difference image between the original image and the upscaled reconstructed image generated by the upscaling unit 130.

The codec determination unit 150 records a codec identifier for identifying a codec used for the base layer encoder 120 to identify a codec used for encoding a header base layer of an upper layer bitstream. In particular, FIG. 2 illustrates an example of codecs used by the base layer encoder 120 according to the codec identifier, where codec identifier 1 is H.264 baseline, codec identifier 2 is H.264 main, and codec identifier, respectively. 3 means VC-1 simple, codec identifier 4 means VC-1 advanced, and codec identifier N means H.263 baseline. In other words, in the case of N codecs from 1 to N, identification is possible, and in the case of unsupported codecs, the codec identifier N + 1 is recorded. At this time, while recording the codec identifier, it is determined whether the codec used for the base layer is a supported codec, that is, a codec capable of symbol extraction.

The symbol extractor 160 determines the base layer bits generated by the base layer encoder 120 when the codec used to perform the base layer encoding is a codec for which enhancement layer encoding is supported. Entropy decoding the stream extracts the symbols used for encoding the base layer bitstream, and corrects the extracted symbols so that they can be used by the enhancement layer encoder 170. In this case, the symbol correction may be different from each other depending on the codec used in the base layer, and even if the characteristics are the same, the scalable vector may be used to determine the size of the motion vector in the frame size or macroblock between the base layer and the enhancement layer. Since there may be a difference in the encoding environment such as the number, a symbol extracted from the base layer bitstream cannot be used for the enhancement layer as it is. Symbols that can be extracted from the base layer bitstream correspond to syntax information common to all existing video criteria. For example, macroblock type information, a motion vector, a coded block pattern (CBP), and a quantized transform coefficient value. And residual information obtained by inverse quantization of transform coefficient values. In this case, the type information of the macroblock indicates the encoding mode of the current macroblock, and whether the macroblock is an inter mode type to which motion prediction and compensation are applied or an intra mode type to which spatial prediction is applied. Say information about it. In addition, in the inter mode type, information about motion compensation, for example, 16x16, 16x8, 8x16, 8x8, etc. may also indicate the block size of the motion vector, or the motion vector such as the forward, reverse, bidirectional, and direct modes. It can also indicate direction or type. The motion vector refers to the displacement between the current macroblock and the corresponding reference macroblock in inter-frame prediction, and the coding block pattern (CBP) indicates the position of a block in which the quantized transform coefficients exist in the macroblock, and at least one quantization Indicates whether the converted transform coefficient is within a block constituting the macroblock.

As shown in FIG. 3, the symbol extractor 160 decodes a first bitstream that decodes a base layer bitstream using a first switch 312, a second switch 313, and an H.264 baseline codec. A second bitstream decoder 310-2, a second symbol corrector, which decodes the base layer bitstream using the H.264 main codec; 311-2, the third bitstream decoder 310-3, which decodes the base layer bitstream using the VC-1 simple codec, the third symbol corrector 311-3, ..., H.263 The N-th bitstream decoding unit 310-N and the N-th symbol correcting unit 311-N decode the base layer bitstream using the baseline codec.

In this case, as an example, the symbol extractor 160 will be described in detail based on the case where the codec used for the base layer encoding is VC-simple. In the following description, the codec used in the base layer encoder may be applied to H.264 baseline, H.264 main and VC-1 advanced.

If the codec used for base layer encoding is VC-1 simple, the first switch 312 connects the base layer encoder 120 with the third bitstream decoder 310-3 and the second switch 313. Connects the third symbol corrector 311-3 to the enhancement layer encoder 170. Then, the third bitstream decoder 310-3 performs entropy decoding on the base layer bitstream, and thus, symbols such as macroblock type information, motion vectors, coding block patterns, and quantized transform coefficient values from the base layer bitstream. Extract The third symbol correction unit 311-3 corrects the extracted symbols so that they can be used by the enhancement layer encoder 170.

As an example of such correction, if the size of the frame of the base layer is different from the size of the frame of the enhancement layer, the third symbol correction unit 311-3 is extracted in consideration of the sizes of the frames as shown in FIG. 4. Correction is performed by mapping the symbols of the base layer macroblocks to the enhancement layer macroblocks.

If the symbol extracted by the third bitstream decoder 310-3 is a motion vector, an example of a method of correcting the motion vector will be described in detail with reference to FIGS. 5A to 5C.

If the number of motion vectors in the macroblock of the enhancement layer and the number of motion vectors in the macroblock of the base layer are the same, the third symbol corrector 311-3 sends the third bitstream decoder 310-3 to the third bitstream decoder 310-3. The motion vectors of the extracted base layer are not corrected.

However, as shown in FIGS. 5A and 5B, when the number of motion vectors in the macroblock of the enhancement layer and the number of motion vectors in the macroblock of the base layer are different from each other, the third symbol correction unit 311-3 may The motion vector of the extracted base layer is corrected to fit the macroblock of the enhancement layer.

Specifically, if the number of motion vectors in the macroblock of the enhancement layer is different from the number of motion vectors in the macroblock of the base layer, the motion vector in the macroblock of the enhancement layer is obtained by using the motion vector in the extracted macroblock of the base layer. Find a new motion vector for the number of. In this case, as an example, if the number of motion vectors in the enhancement layer macroblock is greater than the number of motion vectors in the base layer macroblock, the motion vectors in the extracted base layer macroblock are copied as shown in FIG. Motion vectors in the enhancement layer macroblock. Conversely, as another example, if the number of motion vectors in the enhancement layer macroblock is less than the number of motion vectors in the base layer macroblock, the average of the extracted motion vectors is calculated as shown in FIG. 5B and the mean is expanded. It can be set as the motion vector of the macroblock of the layer.

If the size of the frame of the enhancement layer is different from that of the base layer, the size of the motion vector of the macroblock of the enhancement layer is adjusted in consideration of the size of the frame, for example, as shown in FIG. 5C. Likewise, if the size of the frame of the enhancement layer is twice the size of the frame of the base layer, the motion vector of the enhancement layer can be obtained by multiplying the motion vector extracted from the base layer by two.

The enhancement layer encoder 170 uses the symbols extracted from the symbol extractor 160, that is, the original image or the subtractor 140 by using the information used for encoding the base layer bitstream by the base layer encoder 120. The encoding is performed on the difference image between the original image obtained by and the reconstructed image of the upscaled base layer. According to the present embodiment, examples of information used for encoding the base layer bitstream may include macroblock type information, coded block pattern information, motion vectors, and quantized transform coefficients. However, one of ordinary skill in the art may understand that other information may be included in addition to the above-described information.

In more detail, the enhancement layer encoder 170 encodes the original image or the difference image obtained by the subtractor 140 through predictive encoding, motion compensation, transform and quantization, and the like, such as a motion vector and a quantized transform coefficient. Generates a bitstream comprising a. In addition, the enhancement layer encoder 170 refers to the macroblock type information and the coding block pattern information extracted from the symbol extractor 160, and thus generates the motion vector, the quantized transform coefficients, and the symbol extractor 160. It is determined whether the motion vector and the quantized transform coefficients extracted from R 1 correspond to each other. When it is determined that the enhancement layer encoder 170 corresponds to each other, the enhancement layer encoder 170 uses the motion vector and the quantized transform coefficients extracted from the symbol extractor 160 as prediction values to use the prediction encoding. That is, an enhancement layer bitstream is generated by entropy encoding a subtraction result between each motion vector and a subtraction result between quantized transform coefficients.

In this case, when the motion vector and the quantized transform coefficients extracted by the symbol extractor 160 are similar to the motion vector and the quantized transform coefficients generated by the enhancement layer encoder 170, the coding efficiency may be further improved. .

The bitstream integrator 180 generates an integrated bitstream by integrating the base layer bitstream generated by the base layer encoder 120 and the enhancement layer bitstream generated by the enhancement layer encoder 170.

As described above, the scalable video encoding apparatus according to the present embodiment decodes the base layer bitstream to extract information necessary for enhancement layer encoding, and uses the extracted information to determine a difference between the original video or the original video and the reconstructed video. By performing enhancement layer encoding on an image, a variety of existing codecs are utilized while providing a high quality of service and a high encoding efficiency.

6 is a block diagram illustrating a configuration of a scalable video decoding apparatus according to an embodiment of the present invention.

As shown in FIG. 6, the scalable video decoding apparatus 60 according to the present embodiment includes a bitstream identification unit 610, a base layer decoder 620, an upscaling unit 630, and a codec determination unit 640. ), A symbol extractor 650, an enhancement layer decoder 660, and an adder 670.

The bitstream identification unit 610 identifies whether the input layer includes the enhancement layer bitstream, and if the identification result includes the enhancement layer bitstream, the bitstream is divided into a base layer bitstream and an enhancement layer bitstream. Separate.

The base layer decoder 620 generates a base layer reconstructed image by decoding the base layer bitstream, and the upscaling unit 630 generates an upscaled reconstructed image by performing upscaling on the base layer reconstructed image. In particular, the base layer decoder 620 includes an H.264 baseline profile, an H.264 main profile, a VC-1 simple profile, a VC-1 advanced profile, an MPEG-4 part2 simple profile, an MPEG-4 part2 advanced simple profile, and an MPEG. You can use any codec that is compatible with existing video compression standards, such as the -4 part2 main profile and the H.263 baseline profile.

The codec determination unit 640 extracts a codec identifier for identifying a codec used for encoding the base layer by parsing a header of the enhancement layer bitstream, and the codec according to the extracted codec identifier is supported by enhancement layer decoding. Determine whether or not the codec.

The symbol extractor 650 encodes the base layer bitstream by entropy decoding the base layer bitstream if the codec used to perform the base layer encoding is a support codec available for enhancement layer encoding. A symbol used in the AX is extracted and the extracted symbol is corrected to be used by the enhancement layer decoder 660. The symbol at this time may be type information of a macroblock, a motion vector, an encoding block pattern, and a quantized transform coefficient. As shown in FIG. 3, the symbol extractor 650 extracts a symbol from a base layer bitstream by a first switch 312, a second switch 313, and an H.264 baseline codec. The second bitstream decoder 310-2 and the second symbol that extract symbols from the base layer bitstream by the decoder 310-1, the first symbol corrector 311-1, and the H.264 main codec. A third bitstream decoder 310-3 which extracts a symbol from a base layer bitstream by the VC-1 simple codec, a third symbol corrector 311-3, and the like. The N-th bitstream decoding unit 310-N and the N-th symbol correcting unit 311-N extracting symbols from the base layer bitstream by the H.263 baseline codec. Since it is the same as that described in the symbol extractor 160 of the flexible video encoding apparatus 10, it is omitted.

The enhancement layer decoder 660 uses the enhancement layer bitstream to predict and decode symbols such as the type, motion vector, coding block pattern, and quantized transform coefficients of the macroblock extracted and corrected by the symbol extractor 650. The difference image is reconstructed by decoding.

The adder 670 generates a final reconstructed image by adding the difference image reconstructed by the enhancement layer decoder 660 and the reconstructed image upscaled by the upscaling unit 630.

7 is a flowchart illustrating a scalable video encoding method according to an embodiment of the present invention. Referring to FIG. 7, the scalable video encoding method according to the present embodiment includes steps that are processed in time series in the scalable video encoding apparatus illustrated in FIG. 1. Therefore, although omitted below, the above descriptions of the scalable video encoding apparatus shown in FIG. 1 also apply to the scalable video encoding method according to the present embodiment.

In operation 710, the scalable image encoding apparatus 10 performs downscaling for adjusting image quality of an input original image. A method of lowering a screen resolution, a method of lowering a frame rate of an original image, a method of converting an image format, and a bit depth according to a scalability of the scalable image encoding apparatus 10 to encode an original image by using scalability You can do several downscaling methods, such as reducing the bit depth.

In operation 720, the scalable image encoding apparatus 10 generates a base layer bitstream by encoding the downscaled image, and generates a base layer reconstructed image by decoding the generated base layer bitstream. At this time, in order to perform encoding for generation of a base layer bitstream, an H.264 baseline profile, an H.264 main profile, a VC-1 simple profile, a VC-1 advanced profile, an MPEG-4 part2 simple profile, and an MPEG-4 You can use any codec that is compatible with existing video compression standards, such as the part2 advanced simple profile, the MPEG-4 part2 main profile, and the H.263 baseline profile.

In operation 730, the scalable image encoding apparatus 10 generates an upscaled reconstructed image by performing upscaling on the base layer reconstructed image generated in operation 720. In this case, upscaling refers to performing an opposite process to downscaling in step 710.

In operation 740, the scalable image encoding apparatus 10 obtains a difference image between the original image and the upscaled reconstructed image generated in operation 730.

In operation 750, the scalable video encoding apparatus 10 determines whether the support codec is available for enhancement layer encoding according to the base layer codec used in operation 720, and sets the codec used for encoding the base layer in the header of the higher layer bitstream. Record the codec identifier that allows you to identify it.

In operation 760, if the codec supports the codec according to the extracted codec identifier as a result of the determination in operation 750, the scalable image encoding apparatus 10 encodes the base layer bitstream by entropy decoding the base layer bitstream generated in operation 720. A symbol used in the step S is extracted and corrected so that the extracted symbol can be used for enhancement layer encoding. In this case, the symbol may include type information of a macroblock, a motion vector, a coded block pattern (CBP), a quantized transform coefficient, and the like.

In operation 770, the scalable image encoding apparatus 10 generates an enhancement layer bitstream by encoding the difference image obtained in operation 740, using prediction encoding on the extracted and corrected symbols.

In operation 780, the scalable image encoding apparatus 10 generates an integrated bitstream by integrating the base layer bitstream generated in operation 720 and the enhancement layer bitstream generated in operation 770.

8 is a flowchart illustrating a scalable video decoding method according to an embodiment of the present invention. Referring to FIG. 8, the scalable video decoding method according to the present embodiment includes steps that are processed in time series in the scalable video decoding apparatus illustrated in FIG. 6. Therefore, although omitted below, the above descriptions of the scalable video decoding apparatus illustrated in FIG. 6 also apply to the scalable video decoding method according to the present embodiment.

In operation 810, the scalable image decoding apparatus 60 separates an input bitstream into a base layer bitstream and an enhancement layer bitstream.

 In operation 820, the scalable image decoding apparatus 60 generates a base layer reconstruction image by decoding the base layer bitstream separated in operation 810.

 In operation 830, the scalable image decoding apparatus 60 generates an upscaled reconstructed image by performing upscaling on the base layer reconstructed image generated in operation 820.

 In operation 840, the scalable image decoding apparatus 60 extracts a codec identifier for identifying a codec used for encoding a base layer by parsing a header of the enhancement layer bitstream separated in operation 810. It is determined whether the codec according to the identifier is a codec for which enhancement layer decoding is supported.

In operation 850, if the codec used to perform base layer encoding is a codec supported by the scalable image decoding apparatus 60, the scalable image decoding apparatus 60 may be used to encode the base layer bitstream by entropy decoding the base layer bitstream. A symbol is extracted and corrected so that the extracted symbol can be used for enhancement layer decoding.

 In step 860, when the scalable image decoding apparatus 60 determines that the base layer codec is a codec that can be supported in step 840, the scalable image decoding apparatus 60 uses the codec to predict and decode a symbol extracted and corrected in step 850 and does not support the base layer codec. If it is determined that the symbol is extracted, the difference image is reconstructed by decoding the separated enhancement layer bitstream in step 810.

In operation 870, the scalable image decoding apparatus 60 generates a final reconstructed image by adding the difference image reconstructed in operation 860 and the upscaled reconstructed image generated in operation 830.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a block diagram illustrating a configuration of a scalable video encoding apparatus according to an embodiment of the present invention.

 2 illustrates an example of codecs used by the base layer encoder 120 according to a codec identifier.

3 is a block diagram illustrating a more detailed configuration of the symbol extraction unit 160 according to an embodiment of the present invention.

4 illustrates an example of extracting a symbol by considering a size of a base layer frame and an extended layer frame by the third symbol corrector 311-3 according to an embodiment of the present invention.

5A to 5C are diagrams for describing an example of correcting the extracted motion vector by the third symbol corrector 311-3 according to an embodiment of the present invention.

6 is a block diagram illustrating a configuration of a scalable video decoding apparatus according to an embodiment of the present invention.

7 is a flowchart illustrating a scalable video encoding method according to an embodiment of the present invention.

8 is a flowchart illustrating a scalable video decoding method according to an embodiment of the present invention.

Claims (15)

Generating a base layer bit stream for an image using any one of a plurality of codecs; Determining whether the codec used for generating the base layer bit stream is a support codec available for enhancement layer encoding; Extracting encoding information used to generate the base layer bitstream by decoding the base layer bitstream according to the determination result; And And generating an enhancement layer bitstream of the original image by using the extracted encoding information. The method of claim 1, wherein the encoding information And at least one of macroblock type information, coded block pattern information, a motion vector, and a quantized transform coefficient. The method of claim 1, wherein the determining Determining a type of codec used for encoding by parsing the base layer bitstream; And And determining whether the type of the determined codec corresponds to a supported codec for which enhancement layer encoding is available. The method of claim 1, wherein generating the enhancement layer bitstream And an enhancement layer bitstream is generated by performing encoding on the difference image between the original image and the image reconstructed from the original image by using the extracted information. The method of claim 1, Downscaling the input original image; And And generating a base layer bitstream by encoding the downscaled image. Dividing the input bitstream into a base layer bitstream and an enhancement layer bitstream; Determining whether the codec used for encoding the separated base layer bitstream is a support codec available for enhancement layer decoding; Extracting information used for encoding the base layer bitstream by decoding the separated base layer bitstream according to the determination result; And And decoding the separated enhancement layer bitstream using the extracted information. The method of claim 6, wherein the extracted information is And at least one of block type information, a motion vector, a coding block pattern, and a quantized transform coefficient. A base layer encoder for generating a base layer bitstream for an image using any one of a plurality of codecs; A codec discrimination unit for determining whether a codec used for generating the base layer bitstream is a support codec available for enhancement layer encoding; A symbol extraction unit configured to extract encoding information used to generate the base layer bitstream by decoding the base layer bitstream according to the determination result; And And an enhancement layer encoder configured to generate an enhancement layer bitstream of the original image by using the extracted encoding information. The method of claim 8, wherein the extracted information is And at least one of block type information, a motion vector, a coding block pattern, and a quantized transform coefficient. The method of claim 8, wherein the codec discrimination unit And determining a type of the codec used for the base layer encoding, and determining whether the type of the determined codec corresponds to a supported codec available for enhancement layer encoding. The method of claim 8, wherein the enhancement layer encoder And an enhancement layer bitstream is generated by performing encoding on the difference image between the original image and the image reconstructed from the original image by using the extracted information. The method of claim 8, A down scaling unit for downscaling the input original image; And And a base layer encoder configured to generate a base layer bitstream by encoding the downscaled image. A bitstream separator for separating the input bitstream from the base layer bitstream and the enhancement layer bitstream; A codec determination unit that determines whether a codec used in the separated base layer bitstream is a support codec that can be used for enhancement layer decoding; An information extraction unit for extracting information used for encoding the base layer bitstream by decoding the separated base layer bitstream according to the determination result; And And an enhancement layer decoder configured to perform decoding on the separated enhancement layer bitstream by using the extracted information. The method of claim 13, wherein the extracted information is And at least one of block type information, a motion vector, a coding block pattern, and a quantized transform coefficient. A computer-readable recording medium having recorded thereon a program for executing the method of claim 6 on a computer.

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